fix(content): respect current folder when uploading files (#211)

Previously the dashboard upload always sent files to root (folder_id=NULL)
because the upload flow never read or forwarded the current folder context.
The agency upload already handled this correctly — this applies the same pattern.

Changes:
- api.js: uploadContent() accepts optional folderId, appends to FormData
- content-library.js: handleFiles() passes state.currentFolderId
- content.js: POST / reads folder_id from multipart body

frontend/js/api.js

@@ -83,9 +83,10 @@ export const api = {
     body: JSON.stringify({ parent_id: parentId || null })
   }),
   deleteFolder: (id) => request(`/folders/${id}`, { method: 'DELETE' }),
-  uploadContent: async (file, onProgress) => {
+  uploadContent: async (file, onProgress, folderId) => {
     const formData = new FormData();
     formData.append('file', file);
+    if (folderId) formData.append('folder_id', folderId);
 
     return new Promise((resolve, reject) => {
       const xhr = new XMLHttpRequest();

frontend/js/views/content-library.js

@@ -231,7 +231,7 @@ async function handleFiles(files) {
       await api.uploadContent(file, (pct) => {
         progressFill.style.width = pct + '%';
         progressText.textContent = t('content.upload_progress_named_pct', { name: file.name, pct });
-      });
+      }, state.currentFolderId);
       showToast(t('content.toast.uploaded_named', { name: file.name }), 'success');
     } catch (err) {
       showToast(t('content.toast.upload_failed_named', { name: file.name, error: err.message }), 'error');

server/routes/content.js

@@ -99,7 +99,7 @@ router.post('/', checkStorageLimit, upload.single('file'), async (req, res) => {
     if (!req.file) return res.status(400).json({ error: 'No file uploaded' });
 
     // #73: shared ingest - identical processing + insert for dashboard and agency uploads.
-    const content = await ingestUploadedFile({ file: req.file, userId: req.user.id, workspaceId: req.workspaceId });
+    const content = await ingestUploadedFile({ file: req.file, userId: req.user.id, workspaceId: req.workspaceId, folderId: req.body.folder_id || null });
     res.status(201).json(content);
   } catch (err) {
     console.error('Upload error:', err);